Elevator buffer



I Oct. 10, 1933. H. E. BRANNON 1,929,

ELEVATOR BUFFER Filed May 16 1931 INVENTOR WITNESSES:

{4 HerberzE Brannon.

Patented Oct. 10, 1933 1,929,672 ELEYATORBUFFER Herbert E. Brannon, Oak Park, 111., assignor to 1 Westinghouse Electric Elevator Company, a

corporation of Illinois Application May 16, 1931. Serial No. 537,817

' 5 Claims. (01. 1'8767) My invention relates to buffers for retarding elevator cars at theirlimits of 'travel and more specifically tobufiers of a horizontal type which take up a minimum of space in the pit.

5" 5' It is customary in elevator practice to provide an-oil buffer at each end of the hatchway forengaging the car when it overruns its normal limits of travel, to thereby absorb its kinetic energy and retard it to a smooth stop; The buffers previous- Zmi ly'usedhave been of the'vertical'type and have required a vertical space which is-severaltimes that of'the useful vertical stroke of theb'uifer.

The necessary additional space for the lower bufier was sometimes found by sinking it below 515? the'bottom of the pit, although this involved considerable' expense and trouble, especially when bed rock was encountered. Furthermore, it has sometimes happened that the bottom of the pit was over a subway andit was then impossible to I sink thebuffer.

In any event, the additional space for the upper buifer must be found above the hatchway and can only be provided at considerable expense. Furthermore, elevators are now-being operated at much higher speeds than formerly, and the space required for vertical bufiers which are properly designed to stop high-speed cars ismuch'greater than that required for low-speed buffers. Consequently, the difiiculty of finding suitable space for placing the buffers is increasing-rapidly under modern conditions and must be solved in order to permit progress along other lines.

f It is, accordingly,-an object of my invention to provide an elevator bufferwhich will'occupy a minimum amount of space in the hatchway.

Another object of my-invention is to provide 7 an elevator buffer which may be mounted in a horizontal position in the hatchway.- I I More specifically stated, itis an object of my ries a ram slidably mounted thereon. The ram presents a head which is adapted to be engaged by a striker plate on the bottom of the car. Means is provided for withdrawing the slidable ram as it is depressed by the car in order to maintain the w head constantly in the center of the hatchway.

. invention to provide a horizontal elevator buffer The invention itself, however, both as to its organizationand its method of operation, together with additional objects and advantages thereof,

- will best be understood from'the following description of a specificembodiment, when'read in conjunction with the accompanying drawing, in

which: s v

Figure 1 is a sectional .view-of my device'taken longitudinally through the cylinder. and crank' case; I

Fig. 2 is a side elevational view of my device,- the cylinder crank case and one crankmember being. omitted to show only the ram and its associated mechanism; and Y Fig. 3 is an end viewshowing the slidable ram and its associated mechanism, as the line III-III in Fig. 2.

The apparatus shownin Fig; 1 comprises an} linder l1 and anassociated crank case 12 supported by suitable feet 13. As shown,-this assembly may constitute a compact unitary structuremounted closeto :the. bottom of the pit.-

For convenience of assembly and inspection,,an opening 14 may be provided in the-end .of the crank case which' is closed by a removable cover 15 secured thereto in any conveniently detach? able manner.

A piston 21 is slidably disposed in the cylinder 11, and longitudinally extending groovesi22 are cut in the walls of the cylinder to allow the: oil to escape past the piston when=the buffer is ac-, tuated. The size andv shape of thegrooves 22 are. selected according to the bufier characteristics desired. Instead of the grooves, apertures may be provided to permitthe oil to escape through the cylinder walls, and an outer shell may 'be provided to catch the oil and return it to the crank case, if desired. I

In the lower portion of the crank-case, aheav-y shaft 23'is journalled to support an upwardly-j directed crank 24. The upper or free end of'the' indicated by I crank 24 is connected to the piston; 21-through a' heavy'connecting-rod 26. Since the operation of the device is accompanied by the rotation of the shaft, 23 and crank 24 through :only'a partial rotation of something less than 180,"it is possible to make a very rigid structure by extending the shaft 23 through, and journalling it in both walls of the crank-case. The crank may also be. a rigid structure consisting of a, pair of crank members 24 extending upwardly from the shaft 23 to support opposite ends of the connecting-rod pin 25.

One end of the shaft 23 protrudes from the crankcase l2 and carries a lever arm or ram carstrikerplate 3% on the bottom of the elevator car 35.

As the car descends, its striker plate 34 engages the ram head '33 of the bufier, thereby rotating the ram carriage 31 and the shaft 23 and driving the piston 21 into the cylinder. In order to withdraw the ram head 33 and cause it to remain in alignment with the striker plate 34 in the center of the car, a stationary gear segment 36 is mounted in concentric relation to the shaft 23. The gear segment 36 may be bolted to the side of the crank-case 12 or secured in any convenient manner to prevent rotation. Rack gear teeth 3'? are cut integral with the lower end of the ram. A pinion 38 is supported in simultaneous engaging relation to the rack teeth 37 and the gearsegment 36. As shown in Fig. 3, the pinion 38 is supported by a shaft i0 extending through crank members 39 keyed rigidly to the shaft 23.

As the car causes the ram carriage to rotate, the shaft 23 and cranks 39 are simultaneously rotated, and the pinion 38 is carried around the gear segment 36 in operative engagement therewith. This action causes the pinion 38 to rotate and draw the ram 32 back on the carriage 31, giving the head 33 a vertical descending movement on the center-line, as shown in Fig. 2, until it reaches it final position represented by broken lines. By making the portion of the pinion 38 which engages the gear segment 36 of a different diameter than that portion which engages the rack gear 37 it may be made to retract the ram 32 at any speed desired.

As'the descending car depresses the ram carriage 31 and rotates the shaft 23, the piston 21 is driven back into the cylinder 11, thereby forcing the entrapped oil to escape through the grooves 22 or other passages provided for that purpose. The rate at which the oil can escape limits the speed of rotation of the ram carriage, andretards the car accordingly.

The'actuating mechanism for the buffer constitutes a reducing gear, and the stroke of the piston in the cylinder may therefore, be much less than the useful stroke of the buffer. Since the cylinder 11 is itself mounted in a horizontal position, it is apparent that the vertical space occupied by my buffer is but very little more than the useful stroke of the buffer.

After the device has been actuated to stop a car, it may be retracted to its operative position by any suitable biasing means, such as a helical or spiral spring for lifting the ram carriage or rotating the pinion. It is to be understood that my" buffer may also be mounted in an inverted position above the elevator hatchway for retarding the car at its upper limit of travel. If desired, the ram may be made in two parts to permit greater flexibility for arranging the compensating sheave and cables. The buffer may be mounted on either side of the hatchway next to the wall and permit still greater freedom and space in the pit.

It will be apparent that I have provided an elevator bufier which, because of its reducing gear and horizontal position, requires a minimum amount of space for installation and operation, which does not require an outer chamber for the oil but utilizes the crank-case space, and wherein the ram is receding and maintains the head constantly under the center of the car.

Although I have shown and described a specific embodiment of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In a horizontal elevator buifer, a cylinder, means for mounting the cylinder ina fixed horizontal position adjacent to the end of a hatchway, 'a piston in said cylinder, and vertically actuable means engageable by an-elevator car for moving said piston horizontally, said means comprising a pivoted ram carriage and a .retractable ram carried thereby.

2. In combination with an elevator bufier, a pivoted lever for actuating the buffer, a slidably mounted ram and head. carried thereby for engagement by a car, and means for withdrawing said head as it is depressed by the car to define a rectilinear path.

3. In combination with an elevator buffer, a pivoted lever ,for actuating the buffer, a slidably mounted ram and head carried thereby for engagement by a car, means for withdrawing said head as it is depressed by the car to define a rectilinear path, and speed-reducing mechanism interconnected between the lever and the buffer, whereby the stroke of the buffer may be short, as compared with the usefulstroke of the ram head.

4. In a horizontal elevator buffer, a unitary structure comprising a cylinder, a crank-caseand supporting means, said crank-case serving as an oil reservoir for the cylinder, a piston in said cylinder, a pivoted lever adapted to be disposed in an elevator hatchway, and speed reducing actuating mechanism in said crank case operably responsive to rotation of said lever for driving the piston into the cylinder. 7

5. In a horizontal elevator buffer, a unitary structure comprising a cylinder, a crank-case and supporting meanssaid crank-case serving as an oil reservoir for the cylinder, a piston in said cylinder, a pivoted lever adapted to be disposed in the elevator hatchway, speed-reducing mecha-" nism interconnected between the lever and the piston for driving the piston into the cylinderwhen the lever is depressed, and means for re -Q;

ducing the effective length of said lever as it is depressed, whereby a rectilinear path is described. i

: H. E. BRANNON. 

